1. Field of Art
This invention generally relates to the field of mirror control systems, and specifically relates to high resolution angle sensing for minor control systems.
2. Description of the Related Art
In many active optics applications, minor control systems are used to control the orientation and position of a moveable mirror. In such systems, a minor drive mechanism is used to adjust the minor, and one or more position sensors may be used to precisely measure the resulting orientation and/or position of the mirror.
One type of position sensor used in some minor control systems is a Fabry-Pérot interferometer. In a Fabry-Pérot interferometer, a photocurrent, Ip, is measured from an interference wave generated from the combination of beams from two arms of the interferometer, and the photocurrent is used to determine a distance of interest. However, this measuring approach has several disadvantages. Measuring the distance of interest accurately relies on the exact response shape of the Fabry-Pérot photocurrent, but this shape depends strongly on the physical parameters of the Fabry-Pérot interferometer and the optical components around it. These parameters may vary during operation. Furthermore, due to laser intensity noise, the measurement sensitivity reduces when the detected photocurrent, Ip, is near its peak.
For applications requiring mirror control systems having high speed and accuracy, there is a need for improved systems and methods for quickly steering a mirror and obtaining precise measurement of the mirror's resulting angular position.